Spark plug



Sept. 24, 1929. H. M FULLER 1,729,576

SPARK PLUG Filed July 9,'A 1927 -l-Tfl wvwwm 7 l/ n H g. 6. F2 I r 9 5,m MINIMUM 6 In/manioc Wwd/mu.

Fetented Sept. Z4, l9219 unirse srares PATENT GIFFICE SPARK "SLUGApplication filed July 9, 192'?. Serial No. 204,524.

lily invention relates to spark plugs and h for its object to provide anew and eiiieient spark plug which will have a more intense spark.

l further object is to provide a spark plug which will lire all oi thein the eombustion chamber of an internal combustion engine with a hotterspark than has heretofore been accomplished.

A still 'further object is to provide a spark plug which will beprovided with additional spark gaps which increase the intensity of thespark in the iii-ing chamber.

A still further object is to provide a spark plug which will be providedwith additional spark gaps within the core thereof and which will have astep-up eoil in the Core to intensity the spark.

These objects l accomplish with the device illustrated in t-heaccompanying drawings in which similar numerals and letters ot referenceindicate like parts throughout the several views and as described in thespecification forming a part of this application and pointed out in theappended claims.

ln the drawings in which l have shown the best and most preferred mannerof building my invention, Figure' l is a section oit a spark plug,showing the spark gap therein. Figure 2 is a view ot a double spark gapprovided in a spark plug. Figure 3 is a view of tubular modification ofFigure 2. Figure l is a lsection of a spark plug with a coil between thegap forming two equally spaced gaps between the ends o' the coil and theends of the central wires ot the plug. Figure 5 is a side elevation ofthe coil. Figure 6 is an end view thereof. Figure 7 is a side elevationoit' the contact post.

This application is an improvement over my iii-st invention and patentoit January 18th, ,1927, Serial No. 66.723, Patent No. 1,614,951, dai-edJan. is, 1927.

ln the drawings l have shown the core of the ,spark plug as A, the metalcasing as B, the retaining plug as C and the usual gaskets between theplug and easing. A eore A provided of suitable material, such asporcelain or other composition which will withstand heat and willinsulate and has a eentrai taire theretlufough. @ne eed said bore l isenlarged, as at 2, and is internally threaded. An electrode wire 3,having a flange 4l near one end thereof, is then placed through the corel and the flange e holds the wire in the hole and prevents it from beingpushed too tar through said hole and entirely closes and seals the hole.A threaded Contact post 5 is then provided, having a iange (i thereonand a larger threaded portion 7 on the opposite end thereof. The extremeend ol" the said portion 7 is constricted to form a small Contact post8. The threads of the portion 7 are made to fit in the threaded portionin the enlarged bore 2 of the core A. l3etween the end 8 of the post 5and the end of' the wire 3 I provide a coil of wire 9 which coil is or"large enough diameter to till the hole or bore 2 and so that when thewire 3 and the plug 5 are in place the ends of the coil 9 surround theextreme ends of the wire and plug so-that a spark in bridging the gapbetween them will ump to all sides alike as they are centeredtherearound.

Some modilieations of the device may be made as shown in the drawingsand instead oit' using a coil 9, a solid plug l0 may be inserted betweenthe wire 3 and the plug 5, as shown in Figure et. The inner end of thepost 5 may also be extended longer and a spark gap be made between theends of the port 5 and the wire 3, making a simple single gaptherebetween, as shown in Figure 2.

Other modilications may be made, as shown in Figure 3, where a threadedcylindrical tube 1l is screwed into the core in place of the coil 9,thereby providing two spark gaps, the same as shown in Figure l, butwith a. cylindrical tube to bridge the gap and to carry the current fromthe post 5 to the wire 3. The spark gap is then from the post 5, to thetube ll, te the wire 3 and the tiring gap is between the wire 3 and thecommon spark wire l2 on the metal casing B.

These slight modifications may be made in the invention withoutdeparting from the scope of the claims, the main invention being in thetwo sja-.rk gaps within the core of the t thereby intensifying thespark.

7`ing thus` described my inventifi, l lesi to re by '.letters Fateut ando'iaiu:

l. In a spark plug the combination of a porcelain core, having alongitudinal central bore therethrough with oneend of said bore oflarger diameter than the other and with internal threads therein; a wirepassed through said small bore; a flange on one end ol said wire adaptedto prevent the wire from coming out of said bore; a contact post havingone end larger than the other and threaded to t into said threadedportion of said bore; a coil of wire adapted to be placed within thelarger diametercd bore of said core with the lower end entirelysurrounding said wire but not touching it by contact, and with the topend of said coil entirely surrounding the contact post but not incontact therewith so that when placed the coil is spaced from said wireand said contact post making two spark gaps therebetween.

2. In a spark plug the combination of a metal casing adapted to hold acore therein; a core to it therein being centrally hored with twodiametered holes in alignment therewith; a contact wire on said metalcasing; a wire through the smaller bore of said core spaced from said,Contact wire; a coil carried in said bore of said core surround ing butnot touchingsaid wire; a closure and contact post secured in the top endof said core with the lower end within the cirele of said eoil but notcontacting therewith; and means to connect wires therewith.

In testimony whereof I have affixed my signature.

HARRY M. FULLER,

